Deleting all the records from a table
Often, you'll need to empty a table of all of its records so you can reload the
data. You can do this with a delete
statement with just the table as an argument. For example, in the video, Jason deleted the table extra_employees
by executing as follows:
delete_stmt = delete(extra_employees)
result_proxy = connection.execute(delete_stmt)
Do be careful, though, as deleting cannot be undone!
This is a part of the course
“Introduction to Databases in Python”
Exercise instructions
- Import
delete
andselect
from sqlalchemy. - Build a
delete
statement to remove all the data from thecensus
table. Save it asdelete_stmt
. - Execute
delete_stmt
via theconnection
and save theresults
. - Submit the answer to
select
all remaining rows from thecensus
table and print the result to confirm that the table is now empty!
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Import delete, select
from sqlalchemy import ____, ____
# Build a statement to empty the census table: stmt
delete_stmt = ____
# Execute the statement: results
results = ____
# Print affected rowcount
print(results.rowcount)
# Build a statement to select all records from the census table : select_stmt
select_stmt = select([census])
# Print the results of executing the statement to verify there are no rows
print(connection.execute(select_stmt).fetchall())